(19)
(11) EP 1 143 429 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
21.05.2003 Bulletin 2003/21

(43) Date of publication A2:
10.10.2001 Bulletin 2001/41

(21) Application number: 01108040.5

(22) Date of filing: 29.03.2001
(51) International Patent Classification (IPC)7: G11B 7/135, G11B 7/125
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE TR
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 31.03.2000 JP 2000099580

(71) Applicant: Asahi Glass Co., Ltd.
Tokyo 100-8405 (JP)

(72) Inventor:
  • Shimozono, Hiroaki
    Kanagawa-ku, Yokohama-shi, Kanagawa (JP)

(74) Representative: Müller-Boré & Partner Patentanwälte 
Grafinger Strasse 2
81671 München
81671 München (DE)

   


(54) Objective lens and optical device


(57) An objective lens capable of recording well either CD or DVD wherein a ringed step portion 11 to 15 is provided in a first surface of the objective lens 3, the step portion 11 to 15 has function to produce a phase difference with respect to light having a first wavelength, a ringed step portion 21 to 26 is provided in a second surface of the objective lens 3, and the second step portion 21 to 26 has function to produce a phase difference with respect to light having a second wavelength.






Search report